In the usual approach to welding together successive lengths of pipe to form a pipeline by automatic welding, the welding is performed by providing a carriage which runs about a track mounted around the end of one pipe, and which carries a welding apparatus which is disposed laterally of the carriage at the location of the pipe end joint with another pipe. When the welding carriage is rotated about the track to weld the pipe joint seam the welding tip must be accurately located with respect to the seam and must move without undue vibration along the seam. Welding is usually done by arcuate segments in a selected sequence so that effects of heating do not unduly distort the pipe. The weld bead is usually formed in 90.degree. segments. Opposite 90.degree. segments may be welded at the same time, for which two carriages may be used on the same track. Some weld segments are formed with carriage travel in one direction while others are formed with carriage travel in the opposite direction. The weld segments are preferably slightly larger than 90.degree. in order that small overlaps between the weld segments will be provided. In the use of such equipment, it frequently occurs that the welding tip does not accurately follow the seam, the welding carriage may slip on the track causing burn-throughs at the weld seam, adequate control of welding speed and weld penetration may not be achieved, unwanted vibrations or oscillations of the welding tip may be encountered, and many other unwanted events may occur during the course of making a weld which will detract from the quality of the weld and may take excessive time in making a weld. Because of the insufficiencies of the prior art apparatuses, the apparatus of this invention is provided in an effort to improve the state of the art.